The Research On Brushless Doubly-Fed Machine Adjusting Speed System

The energy sources problem is a great problem that should be settled urgently for the world's developing. Now, as energy sources consume is increasing at fast speed, people have paid great attention on the research of high efficient drive technology. Variable frequency adjusting speed (VFAS) technology is a new technology that springs up following the development of electrical electronic technology and digital processing technology. Among them, the brushless doubly fed VFAS system has most potential. The Brushless Doubly-Fed Machine (BDFM) is a new style machine that integrates the design technology and control strategy based on the cascaded machine. The BDFM system has the robust mechanical characteristics together with controllable speed and power factor, reused slip power and a relatively low rating power converter.The paper has done all-around study on the key technology of BDFM variable frequency system from theory to simulation and has established stability theoretical foundation for continue study work.Firstly, by comparing the latest developing status, the paper drew out that it had great importance to research BDFM VFAS. According to the request of the BDFM system, it put forward and designed the dual PWM converter, which had the ability of dual direction energy flow. It also analyzed the basic theory and mathematic model of three phase voltage PWM rectifier and inducted feedforward control of load current. Simulation testified that the system can meet BDFM drive system's all requests to converter.Secondly, the paper briefly analyzed BDFM's basic theory. Simulation research has been taken for its operation performance and the result indicated that BDFM was very suitable for the use of variable frequency adjusting speed. According to the coordinate transform theory, the paper deduced the BDFM's dual synchronous coordinate math model. By this, it designed the stator flux oriented control strategy and rotor flux oriented vector decoupling control strategy. Simulation testified that the control method had preferable control capability.